Rotary drill.



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GEORG GDNDOS, OF ZURICH, SWITZERLAND.

ROTARY DRILL.

Specification of Letters Patent.

Patented July d, 19t@ Application led October 21, 1914. Serial No. 867,917.

second cutting blade slidably and pivotallyv engaged in said guideway, both blades being held diametrically opposed while they are in adjacentand operative positions, while the second blade is constrained vto move through an angle with respect to the first blade when the former slides downward along said guideway.

illustrated in the accompanying drawing, in which:

Figure l is a 'front View of the rotary drill in working position. Fig. 2 is a horizontal section on line w--w of Fig. 1. Fig. 3 is a similar section on line of Fig. l. Fig. Ll is a similar section on line y-y of Fig. l. Fig. 5 is a 4frontview of the drill partly in section with the cutting blades in their position of rest. Fig. 6 is a horizontal section on line e-z of Fig. 5, and Fig. 7 is a front view at a right angle to Fig. 1 of the upper end of the drill partly in section.

The drill comprises a casing l in which 'l` le preferred forni of my invention is.

the drill rod-ct is provided to which a cutter blade ZJ is attached having a cylindrical guideway coaxially arranged to said drill rod. In said cylindrical guideway a second blade e 1s slidably and pivotally arranged, while a slot and pin connection .c on said guidewa-y is adapted to hold both blades and e diametrically opposed, while they are in their adjacent or operative position. The second blade slides within grooves f f by means of pins g, g and is thus constrained to move through any angle with respect to said irst mentioned blade when sliding downward under its own weight along said guideway What I claim is:

A rotary drill comprising a cutting blade adapted to be attached to a drill rod, a cylindrical guideway onA said blade coaxial with said drill rod, a second cutting blade having slidable and pivotal engagement in said cylindrical guideway, and slot and pin connections provided on said guideway and arranged to hold said blades diametrically opposed while the same are in adjacent and operative position, and to constrain said second blade to move through an angle with ,respect to said first mentioned blade while said second blade slides downward along said guideway.

ln testimony whereof l aix my signature in presence of two witnesses.

GEORG GONDOS.

Witnesses:

CARL GUBLER, CONRAD BAL'rHAUsnR. 

